I have managed to book myself on a ridiculously cheap Alitalia itinerary PRG-MXP-JFK//BOS-FCO-WAW for the third week of March 2012.
If possible, I would like to get a ride on one of DL's DC9s while in the US.
So far the plan is to see the galleries in NY, museums in DC and hopefully get to see an NHL game (ideally either Bruins or Flyers home game).
I know the winter 2011/12 schedule is still far ahead but does anyone have any suggestions how to get on a DC9 flight in the Atlantic Northeast?

Well I dont think DL has DC-9-50's up that way and besides I think they all leave the fleet by the end of this year. They used to fly MKE-MSP, MKE-DTW now not so much.
You might be able to catch a MD-90 or MD-88 out of JFK but not sure. I do know they have the MD-88 on MKE-MSP and MKE-ATL if you wanted to come a bit farther west.

L410Turbolet, During the time period you mentioned, 3/2012, Delta will still operate approximately 20 - 23 DC9-50 aircraft. That is the current plan, which of course, can change rapidly.

As previously mentioned, it is too far in advance to predict the flight schedules for DC9 flights; however, if the schedule remains similar to how it currently is, the majority of DC9 flights will operate in and out of Atlanta. If you are in the New York area, you might be able to pick up a Newark (EWR) - Atlanta (ATL) DC9 trip; or possibly a Baltimore/Washington (BWI) - Atlanta (ATL) flight.

Wait till 3 months in advance, then book yourself on a route that has several daily DC9 departures, book the latest flight. Then show up early, hang out near the boarding areas of the earlier departures and check if they are a DC9, then try to fly standby on the earlier flight.

This will increase your chances.

Soren

All the things you probably hate about travelling are warm reminders that I'm home